This invention relates to a low voltage switching circuit for controlling a high voltage electrical load and more particularly, to a low voltage switching circuit only requiring low voltage electric transmission lines between the high voltage electrical load and a controlling switch or various controlling switches at locations remote from the high voltage electrical load with all high voltage electric transmission lines being confined to supplying high voltage electrical power to the load per se. In one form of the switching circuit, the switch thereof may be a conventional on-off switch. In a more complex, but more advantageous form of the switching circuit, the switch or switches thereof may be a normally off-momentarily on switch or switches connected with certain other components permitting more convenient push-button control. In all forms of the invention, solid state components are extensively used in a unique manner providing maximum compactness, minimum installation expense and maximum overall efficiency.
In substantially all present day residential structures, the same being true of most light commercial structures, the entire electrical wiring thereof is for high voltage electric transmission, for instance, the usual 110 volt alternating current. Virtually no low voltage current, whether alternating current or direct current, is used. One exception to this involves doorbell or door chime circuitry, but obviously, this is of an extremely minor nature.
According to U.S. building standards, 60 volts is the segregation point between high and low voltage, any electrical power 50 volts or above is considered high voltage and anything below 50 volts is considered low voltage. Furthermore, where high voltage electrical power is concerned, the transmission lines must be relatively heavily shielded and insulated due to the greater dangers of arcing and leakage which can result in the consequence of fire and other damage. With low voltage electrical power, the transmission lines therefor, only need be relatively lightly insulated since the foregoing dangers are not present. Thus, in the case of high voltage electric power transmission, the transmission lines are relatively large and bulky, while the low voltage electric transmission lines are relatively small and flexible.
Where only high voltage electrical power is used, this means that the total electrical wiring of the structure must be of the relatively bulky high voltage type, that is, to the particular electrical load for supplying high voltage power thereto and from that electrical load to the switch or switches controlling the same. As an example, consider a ceiling light to be controlled by a wall switch at three or four foot level. The high voltage transmission lines must be directed to the ceiling light for supplying the power thereto and to the wall switch for control of the power, and due to the size, lack of flexibility and bulkiness of the high voltage transmission lines, they can only be positioned recessed within the structure ceiling and recessed within the structure walls. There is little other choice since the size of the high voltage transmission lines would create an unsightly situation unless in this internal ceiling and wall position.
Considering the same example, if the high voltage transmission lines were confined to merely supplying the high voltage power to the load, in this case the ceiling light, and the transmission lines from the ceiling light to the wall mounted switch could somehow be changed to low voltage transmission lines, it is obvious that various advantages could be readily gained. One advantage could be that of cost savings and another that of greater choice of positioning. Only a fraction of the transmission lines would have to be of the heavily shielded and insulated, relatively bulky type which is quite expensive as compared to what could be used for the remaining transmission lines of the relatively lightly insulated and flexible, low voltage type. Furthermore, whereas the high voltage transmission lines in the ceiling would still require recessing totally within the ceiling structure, the low voltage transmission lines could either be recessed within the structure ceiling and walls or positioned directly beneath many types of ceiling, wall and floor coverings to permit maximum versatility while still being totally satisfactory from both safety and aesthetic considerations.